Preparation and characterization of spherical V2O3 nanopowder |
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Authors: | Chenmou Zheng Xinmin Zhang Shan He Qun Fu Deming Lei |
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Institution: | a School of Chemistry and Chemical Engineering, Zhongshan University, Guangzhou 510275, People's Republic of China;b Department of Physics, Zhongshan University, Guangzhou 510275, People's Republic of China |
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Abstract: | V2O3 nanopowder with spherical particles was prepared by reducing pyrolysis of the precursor, (NH4)5(VO)6(CO3)4(OH)9]·10H2O, in H2 atmosphere. The thermolysis process of the precursor in a H2 flow was investigated by thermogravimetric analysis and differential thermal analysis. The results indicate that pure V2O3 forms at 620°C and crystallizes at 730°C. The effects of various reductive pyrolysis conditions on compositions of V2O3 products were studied. Scanning electron micrographs show that the particles of the V2O3 powder obtained at 650°C for 1 h are spherical about 30 nm in size with more homogeneous distribution. Experiments show that nanopowder has larger adsorption capacity to gases and is more easily reoxidized by air at room temperature than micropowder. Differential scanning calorimetry experiment indicates that the temperature of phase transition of nano-V2O3 powder is −119.5°C on cooling or −99.2°C on heating. The transition heats are −12.55 J g−1 on cooling and 11.42 J g−1 on heating, respectively. |
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Keywords: | Ammonium oxovanadium (IV) carbonato hydroxide Thermoanalysis and pyrolysis in hydrogen Spherical V2O3 nanopowder Route of precursor |
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